1. Field of the Invention
The present invention relates, in general, to linear compressors and, more particularly, to a linear compressor in which a piston is linearly reciprocated by a linear motor, and an apparatus to control the linear compressor.
2. Description of the Related Art
Generally, since a reciprocating compressor converts a rotary motion of a motor into a linear motion to operate a piston, an energy loss occurs during a motion conversion procedure, thus deteriorating an energy efficiency thereof. Different from that of the reciprocating compressor, a linear compressor uses a linear motor in which a mover linearly reciprocates, so that a linear motion of a piston is directly connected to the linear motion of the mover of the linear motor without a procedure to convert a rotary motion into the linear motion, thus reducing an energy loss therefrom. As a result, the linear compressor is more efficient than that of the reciprocating compressor.
In the linear compressor, a maximum efficiency may be obtained when a resonance frequency of the linear compressor and a frequency of a drive current supplied to the linear motor are equal. However, since the resonance frequency actually varies due to certain causes, such as a load fluctuation of a piston, a scheme is required to cause the frequency of the drive current to be equal to the resonance frequency of the linear compressor.